Combination telephone transmitter and receiver.



830.58 PATENTED SEPT. 11, 1906 U. G. GILGHREST.

COMBINATION TELEPHONE TRANSMITTER AND RECEIVER. APPLIOATION mum 001212. 1905.

UNITED STATES PATENT orrroa,

CHARLES C. GILCHREST, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, ILLINOIS.

No. scopes.

Specification of Letters Patent.

Patented Sept. 11, 1906. I

Application filed October 12,1905. Serial No. 282,362.

To all wlwm it may concern:

Be it known that 1, CHARLES C. GILOHREST,

a citizen of the United States, residing at.

New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in a Combination Telephone Transmitter and Receiver, of

.which the following is a full, clear, concise,-

and exact description.

i The object of my invention is to overcome the henomenon known as howling in a com ination telephone transmitter and receiver. Howling, or the tandem action between the transmitter and receiver, is due to a variety of causes, the chief of which is the molecular transmission of the vibrations from the receiver to the transmitter, and vice versa, the metal parts of the set and the air column in the handle forming the mediums or vehiclesfor the transmission of such vibrations. This trouble isespecially pronounced in case the transmitter is abnorrnally Inicrophonic or sensitive to vibrations other'than those caused bythe voice-currents directed against the transmitter.

The object of my invention is to' provide a construction whereby the column of air will be vent-ed or left unconfined and whereby the metal connection between the two instruments will be so formed and reduced in crosssection at certain parts as to interrupt the molecular transmission of such sound-vibrations. Y

My invention. will be more readily understood by reference to the accompanying drawing, in which I have shown a combination telephone transmitter and receiverembod ing my invention.

T e handle cconsists of a brass tube 1), with a covering of hard rubber c. The casting d of the transmitter and the casting e of the re cciver are inserted, asshown, a short distance in the opposite ends of said tube and may be held in place by screws from opposite sides. My invention consists in providing the holes or perforations d d, &c., and e e, &c., in these castings. These perforations serve the double purpose of giving vent to the column of air in thetube and of reducing in crosssection the metal connection or medium between the two instruments;

OF. CHICAGO, ILLINOIS, A CORPORATION OF I have made the column of air free and unconfined by providing holes or perforations in the side of the handle. All things considered, I have found it best to provide the circular rows of perforations or'openings cl (1, &o., and e e, &c.,-ini the castings. as shown, in this way practically eliminating the molecular transmission of the vibrations between the instruments and at the same time providing a sufliciently strong handle. The perforations in the castin s are not liable to be covered up by the ban of the user, as would -be the case if located in the handle.

Having thus described my invention, '1- claim as new, and desire to secure by Letters Patent, the following:

1. In a combination telephone transmitter and receiver, the'combination with the cast ings supporting respectively the transmitter and receiver, of a tube forming the handle connecting the same, said castings being each provided with perforations; whereby undue molecular transmission of .the vibrations from he receiver to the transmitter and vice verse. is prevented, substantially as and for the purpose specified.

2. A hand telephone set comprising a transmitter and receiver with their hol supports, and a hollow tube in the opposite ends whereof said supports are inserted, said supportsflhaving air-vents for the column of air therein, to prevent howling between the transmitter and receiver.

In witness whereof I hereunto subscribe my name this 31st day of July, A. D. 1905.

CHAS. C. GILOHREST. Witnesses:

GEORGE A. HAMILTON,

FnANois L. GILMAN. 

